Because the Fraternal Order of Police (FOP), the main union representing law enforcement officers, has been around for almost 100 years, its impact on the conduct of law enforcement has long since been established, and that impact has been minimal in terms of operational effectiveness. The main impact has been financial, as the creation and expansion -- the FOP today represents over 300,000 police officers nation-wide -- of the union over the years has mainly involved increased costs associated with the payment of overtime and other benefits.
Police officers work long, difficult hours, with overtime being standard practice, as the paperwork requirements associated with the profession often extend an officer's shift well-beyond the eight hours routinely spent on patrol. Especially in the event of a major incident, for example, a murder, the hours spent protecting the crime scene, interviewing witnesses, writing reports, etc., can add up to substantial overtime. Without the union, police were uncertain and often unlikely to be compensated for those extra hours on the job.
Similarly, the expansion of the FOP's reach helped law enforcement officers to secure the kinds of routine benefits that most people take for granted today -- or, at least, used to take for granted.
One of the most important contributions of the union for law enforcement is the legal protections it provides when an officer is investigated for possible improper discharge of his or her firearm, in the event of allegations of corruption or of excessive use of force in restraining a suspect. The presence of the union ensures that the officer in question is provided the legal representation needed for preparation of his or her defense.
In addition to the FOP, the history of racism in the United States extended to the treatment of African-American law enforcement officer. The response was the 1972 establishment of the National Black Police Association. Like the FOP, but specific to the concerns of African-Americans, the NBPA ensures that its members are not unfairly discriminated against during promotion cycles and in other ways.
Because both police officers and the cities for which they work recognize the vital role these individuals play in protection public safety, there is generally little incentive for officers to threaten a strike. Grievances are almost always resolved relatively amicably.